Week 6 Pharmacokinetics Flashcards
Steady state concentration definition + definition
When dosing rate is equivalent to elimination rate
ex: 10 mg / min
How many half lives to be eliminated from steady state?
4-5
How many half lives to reach steady state?
4-5
What does increasing infusion rate do?
increases steady state concentration
*has no effect on half-life/time to reach steady state concentration
What effects half lives?
Dependent on volume of distribution and clearance
Increased Vd and half life and SSc
Increased half life
takes longer to reach SSc
Increased clearance and half life
Decreased half life
takes less time to reach SSc
Increased clearance rate and maintenance dose
Higher maintenance dose
Increased bioavailability and maintenance dose
decreased maintenance dose
In renal / hepatic failure, what should be adjusted?
decrease maintenance dose
no change to loading dose
What is loading dose not dependent on?
loading dose is not dependent on clearance
What is maintenance dose not dependent on?
volume of distribution
What 2 factors is loading dose dependent on?
volume of distribution
bioavailability
Loading dose if bioavailability decreases
higher loading dose
Loading dose if Vd decreases
smaller loading dose
*more Vd in serum
What do changes in half life effect?
total time to reach steady state concentration
therapeutic window
difference between toxic threshold and therapeutic threshold
Why is thyroid’s dosing weird?
because it has a small therapeutic window
If your dose interval is below 4 hours, what should you do?
give the drug IV
What might make us want to give a smaller loading dose?
a small therapeutic window
Why do you have to wait to check TSH levels after starting thyroid meds?
thyroid meds have long half life
